Electrical switchgear



Feb. 20, 1951 J. M. CUMMING 2,542,798,

ELECTRICAL SWITCHGEAR Filed Sept. l2, 1946 Patented Feb. 20, 1951 UNITED STATES PATENT OFFICE ELECTRICAL SWITCHGEAR James M. Cumming, Turtle Creek, Pa., assigner to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of 'Pennsylvania Application September 1 2, 1946, Serial-No. 696,572

7 claims. (o1. zoo- 148) type utilizing one or more hollow columns of vitreous insulating material such as porcelain or the like, it is necessary to provide a clamping construction for the columns, either securing them together or attaching one column to a base, which will withstand the jar and shock during circuit interrupting operations, and at the same time will prevent the compressed gas under high pressure from coming between the adjoining porcelain columns to act upwardly and downwardly on the opposed end faces of the columns.

One reason why compressed gas circuit interrupters have not been used as extensively as they might have been is that the constructions utilized have heretofore not had the rigidity and ability to withstand shock as is'possessed by tank type oil circut interrupters. The porcelain columns have a tendency to crack and break under shock and it is diiiicult to provide a gas tight seal between adjoining porcelain columns. Furthermore, it has heretofore been diilicult to secure a ceramic column against a rigid base tousecurely hold the column in position with a gas tight seal and yet to permit a certain amount of flexibility to be achieved'in the mounting arrangement.

The main object of my invention is to provide a gas tight clamping construction to secure two porcelain columns together, or to secure a single porcelain column to a relatively rigid base.

A more specific object is to provide a novel clamping arrangement for hollow columns of vitreous insulating material in which a resilient ring is employed surrounding the outer face of the column which is simultaneously clamped against the column and against either a base or a central support ring, the latter cooperating with another hollow column.

Still another object is to provide novel ange means for each of two adjoining hollow columns composed of a vitried ceramic insulating material so that the two columns may be rigidly secured together, yet permitting some flexibility to be achieved.

Although certain aspects of my invention are particularly adaptable to use in high voltage compressed gas circuit interrupters employing compressed gas up to and in excess of 250 pounds per square inch, nevertheless, other aspects of my invention are of general application and may be used wherever a pair ofgceramic columns need be fastened together or a single column be secured to a relatively rigid base.

Further objects and advantages will readily become apparent upon a readingof the following i specification taken in conjunction with the attached drawing, in which:

vFigure 1 is an elevational view, partially in vertical section, of a compressed gas circuit interrupter embodying my invention and shown in Athe partly open circuit position;

Fig. 2 is an enlarged fragmentary view of the central support ring construction shown in Figure 1;

Fig. 3 is an enlarged view showing more clearly the inwardly extending T-shaped tongue portion of the central support ring of Figure 1;

Fig. 4 is a fragmentary enlarged view of the base support of Figure l; and

Fig. 5 shows, in a fragmentarily enlarged manner, a modified type of clamping arrangement for securing two adioining hollow columns together.

Referring to the drawing and more particularly to Fig. 1 thereof, the reference numeral I designates generally a compressed gas circuit interrupter of the high voltage type being of the type set forth in U. S. patent application, filed January 13', 1945. Serial No. 572.602, issued August 24, 1948, as U. S. Patent 2,447,674, to Albert P. Strom and 'Ihomas E. Browne, Jr., and assigned to the assigneev of the instant application. This type of vcompressed gas circuit interrupter comprises a relatively stationary contact structure 2 cooperating with movable contact structure 3 to establish an arc 4 which is drawn through an oric'e 5 while it is subjected to a blast of compressed gas flowing upwardly as indicated by the arrows 6. This blast of compressed gas enters the interrupter I through the blast tube 8 and passes upwardly around the support 1 for the movable contact structure 3. Suitable means (not shown) provide the flow of compressed gas upwardly through the blast tube 8 in response to movement of the movable contact structure 3. Preferably the relatively stationary contact structure 2 includes a stationary contact 9 of the tulip type in which a plurality of segments are biased inwardly by resilient means. 'I'he movable contact structure 3 preferably includes a rod-shaped movable conducting membei I0 having its lower end secured to a piston (not shown) movable within the support 1 and actuated downwardly by compressed gas.

The casing for the interrupter consists of-a metallic cap structure II having a line terminal i2 integrally formed therewith.- The other line terminal, not shown, for the interrupter is electrically connected to the conducting support 1 for the movable contact structure 3.

Below the cap structure II are positioned two hollow columns I3, I4 composed of a suitable vitreous insulating material such as porcelain, glass or the like. The lower hollow column I4 is mounted upon a base plate I5 which may be secured to other supporting structure, not shown. During the opening and closing operations of the interrupter I, the hollow columns I3, I4 must withstand considerable jar and shock due to the movable contact I0, which moves at high speed, being brought to rest at the ends of its stroke. Also, compressed gas under high pressure passes through the interior of the hollow columns I3, I4. The clamping means I6 securing the two columns together must prevent this gas pressure from entering between the faces I1, I8 of the columns and acting upwardly and downwardly on the columns as indicated by the arrows I9, 20.

The forces exerted by the gas pressure in the direction of the arrows I9, 2|) would be equal to the cross-sectional area of the columns multiplied by the gas pressure in lbs. per square inch. It is, consequently, necessary to prevent the entrance of gas between the opposed faces I1, I8 of the adjoining hollow columns I3, I4 with the clamping means I 6.

Preferably, the clamping means I6, shown more clearly in Figs. 2 and 3, has a central ring of relatively rigid material, such as metal, and designated by the reference numeral 2|. The support ring or relatively rigid member 2| has an inwardly extending T-shaped tongue portion 22 which in the clamped position is interposed between the faces I1, I8 of columns I3, I4. A pair of gaskets 23, 24 of relatively hard, but somewhat yielding material, such as ber, are placed above and below the inwardly extending tongue portion 22 of the central support ring 2l. Thus the faces I1, I8 of the columns I3, I4 do not make direct contact with the metal tongue 22.

At the inner extremity of the T-shaped tongue portion 22 are placed a pair of resilient ring'- shaped gaskets 25, 28 composed of a relatively soft resilient material, such as rubber. The rubber gaskets 25, 26 when compressed by the columns I3, i4 serve to prevent the entrance of gas pressure between the faces I1, I8 of the columns i3. I4. Consequently, there does not result upwardly and downwardly directed forces represented by the arrows I9, 20. The resilient gaskets 25, 25 do not have to withstand the compressive forces between the columns since the load is taken by the harder fiber gaskets 23 and 24, so that the rubber gaskets 25, 26 are not excessively deformed.

The use of the gaskets 23, 24 alone would permit the entrance of gas pressure between the columns i3, I4. However, this is prevented by the soft rubber gaskets 25, 26 which provide a gas tight seal between the columns. A ring of resilient material such as rubber 21 is positioned about the inner end of each column, and a clamping ring 28 is provided for each column to clamp the resilient ring 21 of that column to the central support ring 2| by means of bolts 29. clamping rings 22 preferably are one-piece complete annular members which are movable Cal by the bolts 29 longitudinally of the columns. This causes the rubber rings 21 to be compressed and expand laterally so as to tightly grip the column. Thus the pair of clamping rings 29 not only secure the resilient rings 21 to the outer faces of the columns I3, I4 but also force the resilient rings 21 against the central support ring 2|. After the clampingmeans I6 has been clamped in position, a ring of putty 30 is provided between the outer faces oi. the porcelains I3, I4 and the inner extremity 3| of the clamping rings 28. Following this operation, a coating of metallic paint is painted over the surface of the two rings of putty 30 so that there is electrical contact between the faces 32, 33 of the porcelains I3, I4 and the clamping rings 28.

The rings of putty prevent water from entering between the inner extremity 3| of the clamping rings 28 and the outer faces 32, 33 of the porcelains I3, I4, and the provision of the metallic coating minimizes the formation of corona. Also the rubber rings 21 are preferably formed of a relatively low resistance composition to minimize corona formation.

At the lower end of the porcelain column I4, a similar construction is provided to rigidly clamp the porcelain I4 in position. It will be noted that the hollow porcelain I4 abuts the base or relatively rigid member I5, a ber gasket 34, and a rubber gasket 35 being employed to prevent gas pressure from acting upwardly on the porcelain I4 in the direction of the arrow 35 (Fig. 4). The function of the resilient gasket 35 is the same as the resilient gasket 25, 26 in 'the clamping con'- struction I6 employed for securing the porcelaine I3 and I4 together.

Also in the clamping means 31 resilient ring 21, preferably of rubber', is employed to hold the porcelain I4 in position. .it clamping ring 2B of the same construction as that in the clamping means I6 is employed in conjunction with the rubber ring 21 to force the latter both against the into re :ion 40 ci v face 38 of the porcelain spectively, of porcel shown so that the it. 21 may `flow into the cc rugated constructior The clamping mens .lo emploi/s a ring 3|! of putty to prevent water` from entering hetween the outer ieee (it of the porcelain and the fr finrt 23. The

lic paint Y. el shows i holds top of the ring 3i? is coa to prevent the formatie more clearly the cla the porcelain. it base One important ieature ci my invention is the fact that the rings 2i, 2t are unbroken. Previous clamping constructions were split to get them over the porcelain rain. sheds. By the unltary construction strength is inherent in my improved interrupter.

Fig, 5 shows a modied form of my invention utilized to clamp two porcelaine i3, I4 together. In this modified form of clamping construction, there is employed ilange means 42 at the inner end oi each porcelain. The flange means 42 includes a resilient ring 21 of rubber or the like and a pair of clamping rings 43, 44` for holding the resilient ring 21 against the outer face oi' the column. The two flange means 42 are secured together by bolts 45 and nuts 48 passing through apertures 4l provided in the clamping rings 44'. Each flange means 42 is relatively rigid about its own porcelain. When the two flange means 42 are secured together as by nuts 46 and bolts 45, likewise, the two porcelains I3, I4 are rigidly secured together. It will be observed that with respect to the column I3 the column I4 acts as a relatively rigid member upon which it is supported. Preferably in the construction shown in Fig. 5, a ring 48 of ber or insulating material is employed having a T-shaped inwardly extending extremity. Further, a pair of resilient ringshaped gaskets 25, 26 are used having the same function as the gaskets 25, 26 employed in the clamping means I6 of Fig. 1.

From the foregoing description it will be apparent that I have provided improved clamping means for clamping two porcelain columns together or a single column to a relatively rigid base. With the construction illustrated, compression forces are not exerted by the metal directly against the face of the porcelain. The forces are only indirectly received by the porcelain through the medium of the resilient rings 21. Consequently, there is little tendency for the porcelains to break, and yet with the construction shown, the porcelains are rmly held in the desired position. Furthermore, the construction protects the porcelains against the shock and jar of the opening and closing operations and prevents the high pressure gas from acting upwardly and downwardly upon the porcelains.

It will be apparent that although certain features of my invention are peculiarly adaptable for incorporation in high voltage compressed gas circuit interrupters employing compressed gas under high pressure, nevertheless, certain features of my invention are of general application and may be employed in any construction where two ceramic columns are desired to be securely fastened together or a single ceramic column secured to a relatively rigid base.

Although I have shown and described specific structures, it is to be clearly understood that the same were merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In combination, a pair of ceramic insulating columns adjoining one another through which high pressure gas may flow, ange means about the opposed inner end of each column including a resilient ring and a pair of clamp rings for holding the resilient ring between them in clamping relation and against the outer face of the column, means for securing the flange means of one column to the flange means of the other column, a ring having an inwardly extending T-shaped portion disposed between the columns, and a pair of resilient gaskets disposed against the T portion ofthe ring.

2. In a compressed gas circuit interrupter, a pair of columns composed of ceramic insulating material through which high pressure gas may flow, a central support ring disposed about the columns adjacent their point of engagement and having an integrally formed inwardly extending tongue portion dispsedbetween the columns, a resilient ring disposed about the inner end of each column, and means clamping each resilient ring to the central support ring.

3. In a compressed gas circuit interrupter, a pair of columns composed of ceramic insulating material, means admitting high pressure gas within the columns, a central support ring disposed about thecolumns adjacent their point of engagement and having an integrally formed inv wardly extending T-shaped tongue portion disposed between the columns, a resilient ring disposed about the inner end of each column, means clamping each resilient ring to the central support ring, and a pair of resilient gaskets disposed adjacent the T-shaped tongue portion.

I4:. Ina circuit interrupter of the compressed gas type, a relatively stationary contact, a movable contact separable from the stationary contact to establish an arc, a pair of columns composed of ceramic insulating material, means admitting high pressure gas within the columns to effect extinction of the arc, a central support ring disposed about the columns adjacent their point of engagement and having an integrally formed inwardly extending T-shaped tongue portion disposed between the columns, a resilient ring disposed about the inner end of each column, means clamping each resilient ring to the central support ring, a pair of gaskets of relatively hard but somewhat yielding material placed on opposite sides of the tongue portion against the opposed ends of the columns, and a second pair of gaskets composed of relatively soft resilient material disposed on opposite sides of the inner extremity of the tongue portion adjacent the T-shaped portion of said tongue portion to prevent the entrance of high pressure gas between the opposed ends of the columns.

5. In a circuit interrupter of the compressed gas type, a relatively stationary contact, a movable contact separable from the stationary contact to establish an arc, a relatively rigid member having an inwardly extending portion, a hollow column of ceramic insulating material abutting the relatively rigid member, a ring of resilient material disposed about the end of the column adjacent to the relatively rigid member, a clamping ring for forcing the resilient ring against the end of the column and also against the relatively rigid member, a gasket of somewhat yielding material disposed between the inwardly extending portion of therelatively rigid member and the end of the column, means permitting the flow of high pressure gas through the column to effect extinction of the arc, and a ring-shaped gasket of relatively soft resilient material disposed within the aforesaid gasket to prevent high pressure gas from entering between the end of the column and the inwardly extending portion of the relatively rigid member.

6. In combination, a relatively rigid member, a hollow column of ceramic insulating material having one end thereof facing and supported on the relatively rigid member, said one end being untapered, a ring of continuous resilient rubberlike material disposed about the column adjacent the extreme end thereof, a continuous clamping ring having means forcing the resilient ring laterally against the sides of the column and also holding the column on the relatively rigid member, a gasket of somewhat yielding material positioned between the end of the column and the member of relatively rigid material, a ring-shaped gasket of a resilient material softer than the material of the rst said gasket also positioned between the end of the column and the relatively rigid member and disposed within the first said gasket, and means supplying high pressure gas to the space within the column.

7. In combination, a, relatively rigid member, a hollow column of ceramic insulating material having one end thereof facing and supported on the relatively rigid member, said one end being untapered, e, ring of continuous resilient rubberlike material disposed about the column adjacent the extreme end. thereof, e, continuous clamping ring having means forcing` the resilient ring iatereliy against the sides of the column and also holding the column on the relatively seigle meniber, o. gasket of somewhat yielding materiel posi-f tioned between the enel of the column and the member of relatively rigid materiel, e, ringmsiiepeci gasket of a resilient mateifai softer than tlie me.- terie'i of the first said gasket also positioned be tween the end of the column and the relatively rigid member and disposed Within the first seid gasket, means supplying high pressure gas to the space within the column, and leyei" of oondueizfing paint between the surfe-oe of the column and 'the clamping ring 'to minimize the formation of corone.

8 REFERENCES CITED The following references areo! record in the file of this patent:

UNITED STATES PATENTS Number Name I Date 1,751,379 Allan Mar. 18, 1930 1,788,395 Jansson Jan. 13, 1931 1,953,933 Widmer Mar. 27, 1934 .1,957,982 Smith May 8, 1934 1,972,614 Austin Sept. 4, 1934 2,162,588 Prince June 13, 1939 2,219,171 Balachowsky Oct. 22, 1940 2,306,186 Rankin Dec. 22, 1942 2,321,793 Brandt June 15, 1943 2,395,2@3 Aukers Feb. 19, 1946 2,423,596 Hollingsworth July B, 1947 2,436,306 Johnson Feb. 7, 1948 FQREIGN PATENTS Number Country Date 538,885 Greet Britain Aug. 20, 1941 593,835 Germany Sept. 9, 1933 792,793 France Oct. 28, 1935 

